1. Field of the Invention
The present invention relates to a manufacturing method for a seamless capsule in which a filler material (content) such as a food, health food, pharmaceutical, flavoring, or condiment, is encapsulated by a shell material such as gelatin or agar. In particular, the present invention relates to a manufacturing method suitable for manufacturing an oral quick-dissolving seamless capsule whose shell breaks easily in the oral cavity and dissolves quickly in the mouth to release the filler material into the oral cavity.
2. Background Art
Conventionally, as a technology for manufacturing capsules without seams in the shell, that is, a seamless capsule, and in particular, as a technology suitable for manufacturing a capsule being smaller than a typical soft capsule and larger than a microcapsule, methods and apparatuses for producing seamless capsules enclosing a liquid inner layer have been proposed in the following citations. In these citations, multilayer liquid drops are formed by extruding a multilayer jet from a coaxial multiple nozzle such as a double nozzle, triple nozzle, or the like. The outermost liquid layer of the multilayer liquid drop is hardened by bringing it into contact with a hardening liquid to form a shell.    (1) Japanese Unexamined Patent Application, First Publication, No. Sho 59-11859    (2) Japanese Unexamined Patent Application, First Publication, No. Sho 62-176536    (3) Japanese Unexamined Patent Application, First Publication, No. Sho 62-180744    (4) Japanese Unexamined Patent Application, First Publication, No. Hei 4-322740    (5) Japanese Unexamined Patent Application, First Publication, No. Hei 4-322741    (6) Japanese Unexamined Patent Application, First Publication, No. Hei 5-228360    (7) Japanese Unexamined Patent Application, First Publication, No. Hei 4-338230    (8) Japanese Unexamined Patent Application, First Publication, No. Hei 5-200274    (9) Japanese Unexamined Patent Application, First Publication, No. Hei 5-200275    (10) Japanese Unexamined Patent Application, First Publication, No. Hei 5-200276    (11) Japanese Unexamined Patent Application, First Publication, No. Hei 5-138012    (12) Japanese Unexamined Patent Application, First Publication, No. Hei 6-134292    (13) Japanese Unexamined Patent Application, First Publication, No. Hei 6-154587    (14) Japanese Unexamined Patent Application, First Publication, No. Hei 8-10313    (15) Japanese Unexamined Patent Application, First Publication, No. Hei 8-26976    (16) Japanese Unexamined Patent Application, First Publication, No. Hei 9-155183
Recently, in the field of foods such as sweets, functional foods, or luxury foods and the like, oral quick-dissolving capsules that have a shell easily broken in the oral cavity to release into the oral cavity a filler material such as a food, pharmaceutical, flavoring or the like encapsulated by a shell have been under development. In the medical field, because they can be easily taken without water, this type of oral quick-dissolving capsule has become the focus of attention as a means of delivering medicine to the elderly or infants who have a weakened swallowing capacity or difficulty taking pills. Attempts are being made to manufacture oral quick-dissolving capsules using the manufacturing methods for seamless capsules described above.
However, in manufacturing oral quick-dissolving capsules, manufacture becomes difficult when the shell is made thin and easily dissolved in the oral cavity in order to form a shell that breaks easily in the oral cavity. The reasons are that during manufacture the shell may not be sufficiently hardened, the shell strength may be weak even if it is sufficiently hardened, and the capsule may be deformed or easily crushed during separation from the hardening liquid. In contrast, when a sufficient shell strength is imparted to the shell, the obtained product becomes difficult to break in the oral cavity and an adequate oral quick-dissolving property is not obtained.
In such conventional technology, it is difficult to manufacture a product that has, on the one hand, the oral quick-dissolving property of easily breaking down in the oral cavity, while on the other hand, does not cause problems during manufacture such as incomplete hardening of the shell or being crushed.
In consideration of the problems described above, it is an object of the present invention to provide a manufacturing method for oral quick-dissolving seamless capsules in which a product can be manufactured that has the oral quick-dissolving property of easily breaking down in the oral cavity and does not cause problems during manufacture such as incomplete hardening of the shell or being crushed.